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Jack Steinberger - Biographical

I was
born in Bad Kissingen (Franconia) in 1921. At that time my
father, Ludwig, was 45 years old. He was one of twelve children
of a rural 'Viehhändler' (small-time cattle dealer). Since
the age of eighteen he had been cantor and religious teacher for
the little Jewish community, a job he still held when he
emigrated in 1938. He had been a bachelor until he returned from
four years of service in the German Army in the first World War.
My mother was born in Nuremberg to a hop merchant, and was
fifteen years the younger. Unusual for her time, she had the
benefit of a college education and supplemented the meagre income
with English and French lessons, mostly to the tourists which
provided the economy of the spa. The childhood I shared with my
two brothers was simple; Germany was living through the post-war
depression.

Things took a dramatic turn when I was entering my teens. I
remember Nazi election propaganda posters showing a hateful
Jewish face with crooked nose, and the inscription "Die Juden
sind unser Ungluck", as well as torchlight parades of SA storm
troops singing "Wenn's Juden Blut vom Messer fliesst, dann geht's
noch mal so gut". In 1933, the Nazis came to power and the more
systematic persecution of the Jews followed quickly. Laws were
enacted which excluded Jewish children from higher education in
public schools. When, in 1934, the American Jewish charities
offered to find homes for 300 German refugee children, my father
applied for my older brother and myself. We were on the SS
Washington, bound for New York, Christmas 1934.

I owe the deepest gratitude to Barnett Faroll, the owner of a
grain brokerage house on the Chicago Board of Trade, who took me
into his house, parented my high-school education, and made it
possible also for my parents and younger brother to come in 1938
and so to escape the holocaust. New Trier Township High School on
the well-to-do Chicago North Shore, enjoyed a national
reputation, and, with a swimming pool, athletic fields,
cafeteria, as well as excellent teachers, offered horizons
unimaginable to the young emigrant from a small German
town.

The reunited family settled down in Chicago. We were helped to
acquire a small delicatessen store which was the basis of a very
marginal income, but we were used to a simple life, so this was
no problem. I was able to continue my education for two years at
the Armour Institute of Technology (now the Illinois Institute of
Technology) where I studied chemical engineering. I was a good
student, but these were the hard times of the depression, my
scholarship came to an end, and it was necessary to work to
supplement the family income.

The experience of trying to find a job as a twenty-year-old boy
without connections was the most depressing I was ever to face. I
tried to find any job in a chemical laboratory: I would present
myself, fill out forms, and have the door closed hopelessly
behind me. Finally through a benefactor of my older brother, I
was accepted to wash chemical apparatus in a pharmaceutical
laboratory, G.D. Searl and Co., at eighteen dollars a week. In
the evenings I studied chemistry at the University of
Chicago, the weekends I helped in the family store.

The next year, with the help of a scholarship from the University
of Chicago, I could again attend day classes, so that in 1942 I
could finish an undergraduate degree in chemistry.

On 7 December 1941, Japan attacked the United States at Pearl
Harbor. I joined the Army and was sent to the MIT radiation
laboratory after a few months of introduction to electromagnetic
wave theory in a special course, given for Army personnel at the
University of Chicago. My only previous contact with physics had
been the sophomore introductory course at Armour. The radiation
laboratory was engaged in the development of radar bomb sights; I
was assigned to the antenna group. Among the outstanding
physicists in the laboratory were Ed Purcell and Julian
Schwinger. The two years there offered me the opportunity to take
some basic courses in physics.

After Germany surrendered in 1945, I spent some months on active
duty in the Army, but was released after the Japanese surrender,
to continue my studies at the University of Chicago. It was a
wonderful atmosphere, both between professors and students and
also among the students. The professors to whom I owe the
greatest gratitude are Enrico
Fermi, W. Zachariasen, Edward Teller and Gregor Wentzel. The
courses of Fermi were gems of simplicity and clarity and he made
a great effort to help us become good physicists also outside the
regular class-room work, by arranging evening discussions on a
widespread series of topics, where he also showed us how to solve
problems. Fellow students included Yang, Lee, Goldberger, Rosenbluth, Garwin,
Chamberlain,
Wolfenstein and Chew. There was a marvellous collaboration, and I
feel I learned as much from these fellow students as from the
professors.

I would have preferred to do a theoretical thesis, but nothing
within reach of my capabilities seemed to offer itself. Fermi
then asked me to look into a problem raised in an experiment by
Rossi and Sands on stopping cosmic-ray muons. They did not find
the expected number of decays. After correcting for geometrical
losses there was still a missing factor of two, and I suggested
to Sands that this might be due to the fact that the decay
electron had less energy than expected in the two-body decay, and
that one might test this experimentally. When this idea was not
followed, Fermi suggested that I do the experiment, instead of
waiting for a theoretical topic to surface. The cosmic-ray
experiment required less than a year from its conception to its
conclusion, in the end of the summer of 1948. It showed that the
muon's is a three-body decay, probably into an electron and two
neutrinos, and helped lay the experimental foundation for the
concept of a universal weak interaction.

There followed an interlude to try theory again at the Institute
for Advanced Study in Princeton, where Oppenheimer had become director. It
was a frustrating year: I was no match for Dyson and other young
theoreticians assembled there. Towards the end I managed to find
a piece of work I could do, on the decay of mesons via
intermediate nucleons. I still remember how happy Oppenheimer was
to see me come up with something, at last.

In 1949, Gian Carlo Wick, with whom I had done some work on the
scattering of polarized neutrons in magnetized iron while still a
graduate student at Chicago University, invited me to be his
assistant at the University of California in Berkeley. There the
experimental possibilities in the Radiation Laboratory, created
by E.O. Lawrence, were so great that I reverted easily to my wild
state, that is experimentation. During the year there, I had the
magnificent opportunity of working on the just completed electron
synchrotron of Ed
McMillan. It enabled me to do the first experiments on the
photoproduction of pions (with A.S. Bishop) to establish the
existence of neutral pions (with W.K.H. Panofsky and J. Stellar)
as well as to measure the pion mean life (with O. Chamberlain,
R.F. Mozley and C. Weigand).

I survived only a year in Berkeley, partly because I declined to
sign the anticommunist loyalty oath, and moved on to Columbia
University in the summer of 1950. At its Nevis Laboratory,
Columbia had just completed a 380 MeV cyclotron; this, for the
first time, offered the possibility of experimenting with beams
of T mesons. In the next years I exploited these beams to
determine the spins and parities of charged and neutral pions, to
measure the pi- pi0 mass difference and to
study the scattering of charged pions. This work leaned heavily
on the collaboration of Profs. D. Bodansky and A.M. Sachs, as
well as of several Ph.D. students: R. Durbin, H. Loar, P.
Lindenfeld, W. Chinowsky and S. Lokanathan.

These experiments all utilized small scintillator counters. In
the early fifties, the bubble-chamber technique was discovered by
Don Glaser, and in 1954 three
graduate students, J. Leitner, N.P. Samios and M. Schwartz, and
myself began to study this technique which had not as yet been
exploited to do physics. Our first effort was a 10 cm diameter
propane chamber. We made one substantial contribution to the
technique, that was the realization of a fast recompression
(within ~10 ms), so that the bubbles were recompressed before
they could grow large and move to the top. This permitted chamber
operation at a useful cycling rate. The first bubble-chamber
paper to be published was from our experiment at the newly built
Brookhaven Cosmotron, using a 15 cm propane chamber without
magnetic field. It yielded a number of results on the properties
of the new unstable (strange) particles at a previously
unattainable level, and so dramatically demonstrated the power of
the new technique which was to dominate particle physics for the
next dozen years. Only a few months later we published our
findings on three events of the type Sigma0->
Delta0 + gamma, which demonstrated the existence of
the Sigma0 hyperon and gave a measure of its mass.
This experiment used a new propane chamber, eight times larger in
volume, and with a magnetic field. This chamber also introduced
the use of more than two stereo cameras, a development which is
crucial for the rapid, computerized analysis of events, and has
been incorporated into all subsequent bubble chambers.

In the decade which followed, the same collaborators, together
with Profs. Plano, Baltay, Franzini, Colley and Prodell, and a
number of new students, constructed three more bubble chambers: a
12" H2 chamber as well as 30" propane and
H2 chambers, developed the analysis techniques, and
performed a series of experiments to clarify the properties of
the new particles. The experiments I remember with the most
pleasure are:

- the demonstration of parity violation in D decay, 1957;
- the demonstration of the ß decay of the pion, 1958;
- the determination of the p0 parity on the basis of angular
correlation in the double internal conversion of the g rays, 1962;
- the determination of the w and
j decay widths (lifetimes),
1962;
- the determination of the S0 - D0 relative parity, 1963;
- the demonstration of the validity of the DS = DQ rule in
K0 and in hyperon decays, 1964.

This long chain of bubble-chamber experiments, in which I also
enjoyed and appreciated the collaboration of two Italian groups,
the Bologna group of G. Puppi and the Pisa group of M. Conversi,
was interrupted in 1961, in order to perform, at the suggestion
of Mel Schwartz, and with G. Danby, J.M. Gaillard, D. Goulianos,
L. Lederman and N. Mistri, the first experiment using a
high-energy neutrino beam now recognized by the Nobel Prize, and
described in the paper of M. Schwartz.

In 1964, CP violation was discovered by Christensen, Cronin, Fitch and Turlay. Soon after I found
myself on sabbatical leave at CERN, and proposed, together with
Rubbia and others, to look for the interference between
K0s and K0L
amplitudes in the time dependence of K0 decay. Such
interference was expected in the CP violation explanation of the
results of Christensen et al., but not in other explanations
which had also been proposed. The experiment was successful, and
marked the beginning of a set of experiments to learn more about
CP violation, which was to last a decade. The next result was the
observation of the small, CP-violating, charge asymmetry in
K0L leptonic decay, in 1966. Measurement of
the time dependence of this charge asymmetry, following a
regenerator, permitted a determination of the regeneration phase;
this, together with the earlier interference experiments,
yielded, for the first time, the CP-violating phase jh+ - and, in consequence, as well as
the observed magnitudes of the CP-violating amplitudes in the
two-pion and the leptonic decays, certain checks of the superweak
model. The same experiment also gave a more sensitive check of
the DS = DQ
rule, an ingredient of the present Standard Model.

In 1968, I joined CERN. Charpak had just invented proportional
wire chambers, and this development offered a much more powerful
way to study the K0 decay to which I had become
addicted. Two identical detectors were constructed, one at CERN
together with Filthuth, Kleinknecht, Wahl, and others, and one at
Columbia together with Christensen, Nygren, Carithers and
students. The Columbia beam was long, and therefore contained no
Ks but only KL, the CERN beam was short,
and therefore contained a mixture of Ks and
KL. It was contaminated by a large flux of L0, and so was also a hyperon beam,
permitting the first measurements of L0 cross-sections as well as the
Coulomb excitation of L0 to
S0, a difficult and
interesting experiment carried out chicfly by Steffen and Dydak.
The most important result to come from the Columbia experiment
was the observation of the rare decay KL ->
µ+µ- with a branching ratio
compatible with theoretical predictions based on unitarity.
Previously, a Berkeley experiment had searched in vain for this
decay and had claimed an upper limit in violation of unitarity.
Since unitarity is fundamental to field theory, this result had a
certain importance.

The CERN experiment, which extended until 1976, produced a series
of precise measurements on the interference of Ks and
KL in the two-pion and leptonic decay modes, thus
leading us to obtain highly precise results on the CP-violating
parameters in K0 decay. I believe the experiment was
beautiful, and take some pride in it, but the results were all in
agreement with the superweak model and so did little towards
understanding the origin of CP violation.

In 1972, the K0 collaboration of CERN, Dortmund and
Heidelberg was joined by a group from Saclay, under R. Turlay, to
study the possibilities for a neutrino experiment at the CERN SPS
then under construction. The CDHS detector, a modular array of
magnetized iron disks, scintillation counters and drift chambers,
3.75 m in diameter, 20 m long, and weighing 1200 t, was designed,
constructed, and exposed to different neutrino beams at the SPS
during the period 1977 to 1983. It provided a large body of data
on the charged-current and neutral-current inclusive reactions in
iron, which permitted first of all the clearing away of a number
of incorrect results, e.g. the "high-y anomaly" produced at
Fermilab, allowed the first precise and correct determination of
the Weinberg angle, demonstrated the existence of right-handed
neutral currents, provided measurements of the structure
functions which gave quantitative support to the quark
constituent model of the nucleon, and, through the Q2
evolution of the structure functions, gave quantitative support
to QCD. The study of multimuon events gave quantitative support
to the GIM model of the Cabibbo current through its predictions
on charm production.

In the CDHS experiment we were about thirty physicists. Since
1983, I have been spokesman for a collaboration of 400 physicists
engaged in the design and construction of a detector for the 100
+ 100 GeV e+e- Collider, LEP, to be ready
at CERN in the beginning of 1989. In the meantime I had also
helped to design an experiment to compare CP violation in the
charged and neutral two-pion decay of the
K0L. This experiment was the first to show
"direct" CP violation, an important step towards the
understanding of CP violation.

In 1986, I retired from CERN and became part-time Professor at
the Scuola Normale Superiore in Pisa. However, my chief activity
continues as before in my research at CERN.

I am married to Cynthia Alff, my former student and now
biologist, and we have two marvellous children, Julia, 14 years
old, and John, 11 years old. From an earlier marriage to Joan
Beauregard, there are two fine sons, Joseph Ludwig and Richard
Ned.

I play the flute, unfortunately not very well, and have enjoyed
tennis, mountaineering and sailing, passionately.

This autobiography/biography was written
at the time of the award and first
published in the book series Les
Prix Nobel.
It was later edited and republished in Nobel Lectures. To cite this document, always state the source as shown above.

Addendum, June 2005

In 1988, I was the spokesman of a collaboration
of about 350 physicists, preparing the detector we called ALEPH, which
we had started to plan in 1981, for the CERN electron-positron collider
then under construction called LEP, and which started to operate in 1989.
Altogether, about fifteen hundred physicists participated, using four such
detectors. LEP results dominated CERN physics, perhaps the world's, for a
dozen or more years, with crucial, precise measurements, which confirmed
the Standard Model of the unified electro-weak and strong interactions.
The physics scene had changed a lot since the time of my thesis experiment
in 1948, which I could do quite alone. For some time I could help, as
manager, but also contributing to the detector design and the physics analysis.
This came to an end in 1995, partly because I had no new ideas on the physics
we might learn, and partly because the challenges became more and more technical,
especially in the use of computers, and I could not compete with the younger generation.

Since that time I have enjoyed learning cosmology and
astrophysics, and following its progress. This has given me much satisfaction:
on the one hand it involved having to learn some basic physics new to me, physics
important to cosmology but unimportant in particle physics, such as general relativity
and hydrodynamics, on the other hand these have been spectacular years in astrophysics,
with the discovery in 1992, and continually improving observational results, of the
inhomogeneities of the cosmic microwave background radiation, which give a totally new
map of the universe, at a much earlier time than stars or galaxies, much simpler and
therefore much easier to learn from, and more precisely. I still come to CERN, the 10 km
on my bicycle, every day and sometimes enjoy trying to learn something new.